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  • 1
    Electronic Resource
    Electronic Resource
    Determination of resonance integrals for transanular interactions within semiempirical theories (1981)
    Springer
    Theoretical chemistry accounts 60 (1981), S. 65-71 
    Details
    ISSN: 1432-2234
    Keywords: Resonance integrals ; Cyclophanes ; Molecular π-complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In the present communication of new formula is proposed for the resonance integrals appearing in the π-theoretical treatment of compounds consisting of several weakly interacting conjugated systems. Some implications for semiempirical all-valence schemes are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00554387
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The electronic structures of some extended conjugated electron acceptors within the Hartree-Fock approximation and beyond the mean-field approach as verified by the Hartree-Fock instabilities (1984)
    Springer
    Theoretical chemistry accounts 66 (1984), S. 51-64 
    Details
    ISSN: 1432-2234
    Keywords: Extended conjugated electron acceptors ; electronic structure in the INDO and π-electronic approximations ; Hartree-Fock instabilities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electronic structures of the extended conjugated electron acceptors1–3 were investigated within the framework of a semiempirical INDO and a π-electronic Hartree-Fock Hamiltonian. Utilizing Koopmans' theorem, predictions are made of the magnitude of the ionization potentials and the electron affinities and their dependence on the molecular geometry (“olefinic” vs. “aromatic”) and the nature of the acceptor functions. The validity of the Hartree-Fock approximation has been studied by means of the Thouless stability conditions. The INDO and π-SCF wave functions turn out to be adequate descriptions of the ground states of1–3. A single particle hole pair, due to a small energy separation between the highest occupied and lowest virtual orbital and a large Coulomb integral with respect to these orbitals leads to non-singlet (triplet) instabilities or near instabilities of the wave functions indicating the importance of spin correlation in1–3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00577139
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The conjugated circuits model (1988)
    Springer
    Theoretical chemistry accounts 73 (1988), S. 437-448 
    Details
    ISSN: 1432-2234
    Keywords: Annelted [n]annulenes ; Chemical graph theory ; Conjugated circuits model ; Kekulé structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Several annelated [n]annulenes are examined from a graph-theoretical point of view. It is shown how a new interpretation of the conjugated circuit model can be used in order to study the geometries of such compounds. The work illustrates which energetical factors determine whether a structure with alternating bond lengths, or with reduced symmetry is more stable than one with full double bond delocalization or full symmetry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00527747
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Konjugation in makrocyclischen Bindungssystemen [1] (1974)
    Springer
    Theoretical chemistry accounts 35 (1974), S. 189-202 
    Details
    ISSN: 1432-2234
    Keywords: Chemical shift ; Magnetic susceptibility ; Degenerate eigenvalues ; Circumpolyacenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A simple formula (14) has been derived for the calculation of the perturbed first order orbitals, which is applicable to systems with degenerate unperturbed eigenvalues. With formula (14) it is possible to calculate second order energy-derivatives like chemical shifts or magnetic susceptibilities for systems with degenerate eigenvalues without any extrapolations. This formula has been applied to the calculation of 1H-chemical shifts of Circumpolyacenes, which have degenerate HMO- and SCF-eigenvalues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00546904
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Notizen: Elektron-Donor-Acceptor-Verbindungen, XL. Theoretische Deutung der Charge-Transfer-Absorptionen von syn- und anti-Donor-Acceptor-Metacyclophanen (1985)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 1254-1260 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electron Donor-Acceptor Compounds, XL. Theoretical Explanation of Charge-Transfer Absorptions of syn- and anti-Donor-Acceptor MetacyclophanesThe similarity of charge-transfer absorptions which in spite of the very different donor-acceptor arrangement has been observed for syn-anti isomeric donor-acceptor metacyclophanes (1-4) is explained by the aid of simple theoretical considerations.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19851180338
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